var a = require('./a')
var a = require('./a')
var a = require('./a')
var a = require('./a')
var a = require('./a')
var a = require('./a')
var a = require('./a')
var a = require('./a')
var a = require('./a')


var a = new Map()
{
    原始要拷贝的对象作为属性名:深拷贝之后对象
}